It is with trepidation that I ask this question….it’s been asked innumerable times before, including on this site. I’ve just spent hours perusing the cyberspace rabbit hole and it seems there is zero consensus. DO I need C-Channel supports for my live edge slab (which will ultimately be used as an office desk)?
My project is a medium sized slab – 50″ X ~26″ walnut, exactly 1 1/2″ thick after milling and leveling. It’s constructed of three pieces from the same tree, the widest portion being about 14″. It began as a 2″ slab, kiln dried, with moisture content just less than 8%.
I am about ready to install the legs — four individual legs from Flowyline, each with 13″ X 5″ mounting plates. I offer this information because I assume those large mounting plates will add some rigidity.
Because this is not an exceptionally large piece and because final project is constructed of three pieces, I had not planned to install the c-channels but am having second thoughts.
Marc Spagnuolo (the Wood Whisperer) posted a video not only refuting the need for C-channels but some of his readers even opined that it might weaken the slab. I’m not worried about the extra work or cost, but just wondering, if those readers have a point.
Is it necessary on a smallish slab? Thoughts? Any consensus out there…
Replies
50" long, 26"wide and 1.5" thick glued-up walnut slab is strong enough to dance on. If it's flat and stable it's probably gonna stay that way. Check the Sagulator if you're wondering what kind of load it will take to bend it.
Guess I did not make clear the exact nature of my query. I'm not worried about the slab handling a load. I'm more concerned with warpage/cupping over time. It's my understanding that a C-channel prevents or minimizes wood movement.
It's just KD lumber, if it's flat and stable after milling it will probably stay that way. Trying to keep wood from moving is a mistak.
Agree that KD dried stuff will stay stable but if you wish to add an extra layer to be safe, consider a 1/2" thick, ~20" long, cross-member sandwiched between the 13" mounting plates and the 26" wide top. Use a solid straight grain such as QSWO and screw it in from the bottom with slots to allow seasonal movement.
Me thinks that if you mentioned "c channel" to George Nakashima a giant question mark would light up over his head!